DOPI (Double 0, Pass 1)

DOPI is the acronym for "Double = 0, Pass = 1." It is a convention used after partner bids 4NT Blackwood or 4 Gerber to ask for aces, but the next player overcalls (usually in a sacrifice attempt). Using DOPI, responder has the following calls available:

Call	Meaning
Double	0 aces
Pass	1 ace
Cheapest bid over the overcall	2 aces
Second-cheapest bid	3 aces
Third-cheapest bid	4 aces

If playing Roman Key Card Blackwood, the responses are:

Call	Meaning
Double	0, 3 or 5 keycards
Pass	1 or 4 keycards
Cheapest bid over the overcall	2 keycards without the trump queen
Second-cheapest bid	2 keycards with the trump queen

If partner bids 4NT followed by 5NT, he is making a Blackwood query for kings. All other rebids by partner are natural signoffs.

DOPI is more informative than DEPO, but the drawback is that it can't be played when the opponents compete above 5 of your trump suit. For example:

5 KQT5 AT987 A63

You     1 ? LHO     3 Partner     4NT RHO     6

When this occurs, it's better to switch to DEPO, or to simply play DEPO all the time.